I only use contacts occasionally, for snowboarding and windsurfing. I use daily disposable for windsurfing (I can toss them when they get soaked in lake water), weekly for other uses. I often keep a spare pair of contacts in my day pack. I wouldn't expect to use them in a survival situation though, since my hands would probably not be clean enough. If my eyes were worse than they are (20/50 or so), I would probably put a spare pair of glasses in my emergency kit.

Anyways, the factory packaging seems quite durable, I haven't had one leak yet. The plastic storage cases also seem to keep quite well. I've pulled out a pair that's been soaking in cleaning solution for a year and used them with just a quick rinse in saline.